Concrete building block



3. Concrete building block

3.1 : Perspective

3.2 : Front

3.3 : Back

3.4 : Top

3.5 : Bottom

3.6 : Right

3.7 : Left

3.8 : Cross sectional

The broken lines shown in FIGS. 3.1-3.8 illustrate portions of the concrete building block that form no part of the claimed design. 

CLAIM The ornamental design for a concrete building block, as shown and described. 